The present disclosure relates, in various embodiments, to an imaging member or apparatus and fuser components thereof. In particular, the present disclosure relates to a fuser member that includes a high gloss coating layer comprising a haloelastomer and filler particles of a certain size and hardness. A fuser member in accordance with the present disclosure is suitable for use in electrostatographic and xerographic printing processes and is described with particular reference thereto. It is to be appreciated by persons skilled in the art that fusers in accordance with the present disclosure are amenable to any image forming apparatus including color image forming devices.
In a typical electrostatographic reproducing apparatus, a light image of an original to be copied is recorded in the form of an electrostatic latent image upon a photosensitive member and the latent image is subsequently rendered visible by the application of electroscopic thermoplastic resin particles which are commonly referred to as toner. The visible toner image is then in a loose powdered form and can be easily disturbed or destroyed. The toner image is usually fixed or fused upon a support, which may be the photosensitive member itself, or other support sheet such as plain paper.
The use of thermal energy for fixing toner images onto a support member is well known and methods include providing the application of heat and pressure substantially concurrently by various means such as, for example, a roll pair maintained in pressure contact, a belt member in pressure contact with a roll, a belt member in pressure contact with a heater, and the like. Heat may be applied by heating one or both of the rolls, plate members, or belt members. With a fixing apparatus using a thin film in pressure contact with a heater, the electric power consumption is small, and the warming-up period is significantly reduced or eliminated.
It is important in the fusing process that minimal or no offset of the toner particles from the support to the fuser member take place during normal operations. Toner particles offset onto the fuser member may subsequently transfer to other parts of the machine or onto the support in subsequent copying cycles, thus increasing the background or interfering with the material being copied there. The referred to “hot offset” occurs when the temperature of the toner is increased to a point where the toner particles liquify and a splitting of the molten toner takes place during the fusing operation with a portion remaining on the fuser member. The hot offset temperature or degradation of the hot offset temperature is a measure of the release property of the fuser, and accordingly it is desired to provide a fusing surface, which has a low surface energy to provide the necessary release. To ensure and maintain good release properties of the fuser, it has become customary to apply release agents to the fuser roll during the fusing operation. Typically, these materials are applied as thin films of, for example, silicone oils to prevent toner offset.
Another important method for reducing offset is to impart antistatic and/or field assisted toner transfer properties to the fuser. However, to control the electrical conductivity of the release layer, the conformability and low surface energy properties of the release layer are often affected.
Known fuser coatings include high temperature polymers such as polytetrafluoroethylene, perfluoroalkoxy, fluorinated ethylene propylene, silicone rubber, fluorosilicone rubber, fluoroelastomers, and the like: These coatings have been found to have adequate release properties and control toner offset sufficiently. However, problems have resulted with known fuser member layers, including that the fuser member prematurely hardens resulting in a life short fall. Some known fuser members have also been shown to show a susceptibility to contamination, scratching and other damage. Further, silicone rubber layers tend to swell upon application of release agents. Moreover, fuser members have been shown to provide toner offset or inferior release capability, which allows for inappropriate copies and/or prints, and toner contamination to other parts of the machine.
One of the problems associated with fuser rolls coated with, for example, a fluoroelastomer, is that such coatings have a failure mode where the prints develop noticeable gloss variation as the coating wears. While even the worn areas of a fuser rolls often yield absolute gloss that is within the specification or tolerance limits of an imaging apparatus, a variation of as little as 2 gloss units is detectible by the human eye and may be deemed a failure or unacceptable result.
Extending the wear life of the fuser roll has been achieved in the past by distributing the wear. For example, wear life of the fuser roll has been achieved by moving the paper edge or accessories relative to the rollers, using very low loading force on sensors and fingers in contact with the surfaces, and using retractable members such as stripper fingers.
Additionally, various compositions comprising a polymer and a filler have been used in the production of a fuser component of an imaging member. Among others, these include:
U.S. Pat. No. 5,217,837, the disclosure of which is incorporated herein by reference in its entirety, describes a multilayered fuser member for fusing thermoplastic resin toner images to a substrate in a fuser system of the type wherein a polymeric release agent having functional groups is applied to the surface of the fuser member. The fuser member includes a base support member, a thermally conductive silicone elastomer layer, an amino silane primer layer, an adhesive layer and an elastomer fusing surface comprising poly (vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene), and a metal oxide present in the fusing surface to interact with the polymeric release agent to provide an interfacial barrier layer between the fusing surface and the toner and substantially unreactive with the elastomer.
U.S. Pat. No. 5,219,612, the disclosure of which is incorporated herein by reference in its entirety, discloses a multilayered fuser member having a base support member, an adhesive comprising a copolymer of vinylidene fluoride and hexafluoropropylene and at least 20% by weight of the adhesive layer of a coupling agent comprising at least one organo functional silane and an activator, a tie coat layer of active ingredients comprising a copolymer of vinylidene fluoride and hexafluoropropylene and an outer elastermeric fusing surface comprising a copolymer of vinylidene fluoride and hexafluoropropylene and containing a metal oxide present in an amount sufficient to interact with a polymeric release agent having functional groups to provide an interfacial barrier layer between the fusing surface and the toner.
U.S. Pat. No. 5,332,641, the disclosure of which is incorporated herein by reference in its entirety, describes a fuser member having an aluminum base member and an elastomer fusing surface of a poly(vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene) where the vinylidene fluoride is present in an amount of less than 40 mole percent, an adhesive layer between the surface of the aluminum base member and the elastomer fusing surface. The elastomer fusing surface may include metal oxide filler particles.
U.S. Pat. No. 5,595,823 describes a fuser member that includes a core and a layer overlying the core. The layer overlying the core includes a cured fluorocarbon random copolymer with certain fluorinated subunits, and a particulate filler that includes aluminum oxide and a material selected from the group consisting of alkali metal oxides, alkali metal hydroxides, and combinations thereof.
U.S. Pat. No. 5,998,033 describes a fuser member wherein the outermost layer comprises a fluoroelastomer with thermally conductive metal oxide fillers and a silane coupling agent that is interactive with the fluoroelastomer and with an optional release agent.
U.S. Pat. No. 6,011,946, the disclosure of which is incorporated herein by reference in its entirety, is directed to a fuser member having a substrate and a filled polymeric outer layer over the substrate, wherein the filled polymeric outer layer includes a zinc compound disbursed therein. The fuser member also includes a fluid release agent with molecules having amino functionality.
U.S. Pat. No. 6,096,429 is directed to a fuser member having a core and a layer overlying the core wherein the layer overlying the core includes a cured fluorocarbon random copolymer having certain fluorinated subunits. The layer overlying the core incorporates particulate filler that includes zinc oxide, cupric oxide and a material selected from the group consisting of alkali metal oxides, alkali metal hydroxides, and combinations thereof. The filler has a total concentration in the layer of 12% to 75% of the total volume of the layer.
U.S. Pat. No. 6,218,014 describes a fuser member comprising a support and coated thereon a fluorocarbon elastomer layer containing a silicon carbide filler and a cupric oxide filler, and/or a silicon carbide filler treated with a silane coupling agent having a reactive functional group. The fuser member further includes a functionalized polydimethylsiloxane release agent applied to the fluorocarbon elastomer layer in an amount sufficient to produce, upon incubation at elevated temperature, a surface having improved toner release properties on said outermost layer.
U.S. Pat. No. 6,582,871 is directed to a process for fusing toner to paper. The '871 patent describes a fuser member comprising a base, and a fusing surface layer comprising at least one fluoroelastomer and Fe2O3 filler.
U.S. Pat. Application Publication No. 2004/0023144 discloses a fuser member comprising a core and a pliant coating thereon. The coating comprises a base cushion layer comprised of a first elastomeric composition, with a surface layer thereover comprised of a second elastomeric composition. The surface layer may include a particulate silica filler in an amount of about 10 volume percent or less, based on the total volume of the surface layer.
U.S. Pat. No. 6,829,466, the disclosure of which is incorporated herein by reference in its entirety, describes a fuser component useful in electrostatic graphic machines having an optional substrate, an optional intermediate and/or adhesive layer, and a layer of high temperature plastic such as epoxy, polyketone, polyether, polyamide, and polyparabanic acid. A low surface energy filler, including carbon fillers, metals, metal oxides, doped metal oxides, ceramics, polymer fillers, and nanofillers, may be present in the high temperature plastic layer.
U.S. Pat. No. 6,838,140, the disclosure of which is incorporated herein by reference in its entirety, describes a fuser component having a substrate and a silicon rubber layer over the substrate. The silicon rubber layer has a crosslinked product of at least one platinum catalyzed additional curable vinyl terminated polyorganosiloxane, aluminum oxide fillers, iron oxide fillers, cross linking agent, and an optional outer fluoroelastomer layer.
U.S. Pat. Application Publication No. 2004/0109057, the disclosure of which is incorporated herein by reference in its entirety, describes marking apparatuses and processes for providing a layer on a marking member. The publication application describes a process for providing a layer on a marking member that comprises dissolving a fluoroelastomer, adding and reacting a nano-size zinc oxide as a cross linking agent to form a resulting homogeneous fluoroelastomer dispersion, wherein the nano-size zinc oxide has a particle size of from about 1 to about 250 nanometers, and subsequently providing at least one layer of the homogeneous fluoroelastomer dispersion to the marking member.
U.S. Pat. Application Publication No. 2004/0109055, the disclosure of which is incorporated herein by reference in its entirety, describes an imaging apparatus and layer thereof for use in offsent printing or inkjet printing apparatuses. An imaging member includes an imaging substrate, and thereover an outer coating comprising a nano-size filler having an average particle size of from about 1 to about 250 nanometers.
U.S. Pat. Application Publication No. 2003/0207078, the disclosure of which is incorporated herein by reference in its entirety, describes a fuser member having a polyimide substrate, and thereover an outer layer with from about 61 to about 99 volume percent fluorocarbon. A low surface energy filler and/or electrically conducted filler and/or chemically reactive filler may be present in the fluorocarbon outer layer, including carbon fillers, metals, metal oxides, doped metal oxides, ceramics, polymer fillers, and nanofillers.
U.S. Pat. Application Publication No. 2003/0049056, the disclosure of which is incorporated herein by reference in its entirety, describes a fuser component having a substrate, an optional intermediate and/or adhesive layer, and an outer polyimide layer. The outer polyimide layer may include a filler including carbon fillers, metals, metal oxides, doped metal oxides, ceramics, polymer filters, and nanofillers.
A need remains, however, for fuser components for use in electrostatographic machines that have superior mechanical properties. Further, a need remains for fuser coatings having reduced susceptibility to contamination, scratching, and other damage. In addition, a need remains for a fuser component having a longer life. Even further, a need remains for a fuser component that maintains high gloss even as the surface is worn by media or other hardware within the fuser subsystem.